Long-term Prediction of Sea-Level Changes around the Korean Peninsula over the Next One Million Years using a Conceptual Global Sea-Level Model

This study presents long-term projections of global and regional sea level changes over the next one million years using a conceptual global sea level model, and evaluates the corresponding shoreline variations around the Korean Peninsula. The global ice-volume variations over the past one million years were first simulated using a conceptual global ice-volume model, and the modeled results show a strong correlation with proxy-based global sea level reconstructions, with correlation coefficients of –0.78 for the past 800 kyr and –0.81 for the past 500 kyr, confirming the model’s long-term reproducibility. Future simulations applying five Shared Socioeconomic Pathway (SSP) greenhouse gas scenarios indicate that under low-emission scenarios (SSP1–2.6 and SSP2–4.5), the next glacial inception is expected to occur approximately 50–60 kyr from the present. In contrast, under high-emission scenarios (SSP3–7.0 and SSP5–8.5), the onset of the next glaciation is delayed until 120–170 kyr in the future. Notably, the SSP5–8.5 scenario projects an exceptionally prolonged interglacial period lasting over 100 kyr, with a global mean sea-level rise of up to 24 m that persists for an extended duration. Based on these results, the future shoreline configurations around the Korean Peninsula were reconstructed. Depending on the scenario, global sea level is projected to rise by approximately 12–21 m within the next millennium, resulting in a marked inland retreat of coastlines, particularly along the western and southern coasts of Korea, including the Hwanghae and Chungcheong regions. After 50 kyr, certain scenarios show coastal expansion due to sea-level fall, while after 100 kyr, the progression toward the next glacial maximum leads to a complete exposure of the Yellow Sea basin.